//taxi
int main() {
  int persons;
  //printf("%d\n",persons);
  int cars = 0;
  scanf("%d", &persons);
  //cars=(persons+3)/4;//Method2
  if (persons % 4 == 0)
   { //Mothod1
    cars = persons / 4;
  } else {
    cars = persons / 4+1;
  }
  printf("cars=%d\n", cars);
  return 0;
}
